1. Field of the Invention
The present invention relates to a universal steering and propulsion unit for use with marine craft. The system is universal in the sense that it may be installed wherever the propeller thrust is needed and gives the operator immediate control of the amount and direction of propeller thrust. It is universal also in the sense that it may be mounted either inboard or outboard of the boat hull. More particularly, the propulsion unit utilizes a source of motive power such as an internal combustion engine and a power train which includes a differential gearing unit with control of the power delivered being accomplished through selective braking of one side of the differential. Steering may be accomplished by a 360.degree. rotating ability of the propeller without interruption of the power delivered to the propulsion unit. The power train also provides a special gearing arrangement whereby the propeller drive shaft may be driven so as to provide forward thrust regardless of the direction of rotation of the output drive shaft of the power unit, thus obviating the necessity for oppositely rotating output shafts when dual drive units are required.
The invention also includes a novel sealing arrangement for the propeller shaft which takes advantage of centrifugal force to direct seeping fluid away from the shaft. Another novel feature of the invention is the use of the oil pressure about the propeller shaft and gear transfer housing for feathering the propeller blades.
2. Description of the Prior Art
Although prior art marine propulsion systems have been devised which utilize either a constant speed power source and a clutch arrangement for disengaging the propeller shaft from the power source or such devices as variable speed electrical motors directly coupled to the propeller shaft, the most common arrangement involves a power source such as an internal combustion engine, a clutch and a transmission assembly for varying the power to the propeller shaft as well as the direction of rotation. The problem of directional thrust or reverse thrust has also been solved in some instances by providing a propeller assembly which will rotate through 360.degree., thus providing directional thrust from a constant speed power source. Such examples are U.S. Pat. No. 1,021,408 to Haschke, U.S. Pat. No. 2,930,342 to Wanzer, U.S. Pat. No. 3,415,216 to Strobel, U.S. Pat. No. 3,723,839 to Cramer, and U.S. Pat. No. 1,034,987 to Ducasson.